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Implement basic getblocktemplate BIP0022 support.

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This commit implements the non-optional and template tweaking support for
the getblocktemplate RPC as defined by BIP0022.  This implementation does
not yet include long polling support.

This is work towards #124.
This commit is contained in:
Dave Collins 2014-06-27 14:12:22 -05:00
parent 3a45ec1058
commit eb7ecdcc22
3 changed files with 422 additions and 21 deletions
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6
blockmanager.go
View file

@ -1129,9 +1129,9 @@ func (b *blockManager) handleNotifyMsg(notification *btcchain.Notification) {
}
if r := b.server.rpcServer; r != nil {
// Now that this block is in the blockchain we can mark all the
// transactions (except the coinbase) as no longer needing
// rebroadcasting.
// Now that this block is in the blockchain we can mark
// all the transactions (except the coinbase) as no
// longer needing rebroadcasting.
for _, tx := range block.Transactions()[1:] {
iv := btcwire.NewInvVect(btcwire.InvTypeTx, tx.Sha())
b.server.RemoveRebroadcastInventory(iv)

14
mining.go
View file

@ -319,6 +319,20 @@ func logSkippedDeps(tx *btcutil.Tx, deps *list.List) {
}
}
// minimumMedianTime returns the minimum allowed timestamp for a block building
// on the end of the current best chain. In particular, it is one second after
// the median timestamp of the last several blocks per the chain consensus
// rules.
func minimumMedianTime(chainState *chainState) (time.Time, error) {
chainState.Lock()
defer chainState.Unlock()
if chainState.pastMedianTimeErr != nil {
return time.Time{}, chainState.pastMedianTimeErr
}
return chainState.pastMedianTime.Add(time.Second), nil
}
// medianAdjustedTime returns the current time adjusted to ensure it is at least
// one second after the median timestamp of the last several blocks per the
// chain consensus rules.

423
rpcserver.go
View file

@ -63,6 +63,23 @@ const (
// padding format.
hash1Len = (1 + ((btcwire.HashSize + 8) / fastsha256.BlockSize)) *
fastsha256.BlockSize
// gbtRegenerateSeconds is the number of seconds that must pass before
// a new template is generated when the previous block hash has not
// changed and there have been changes to the available transactions
// in the memory pool.
gbtRegenerateSeconds = 60
)
var (
// gbtCoinbaseAux describes additional data that miners should include
// in the coinbase signature script. It is declared here to avoid the
// overhead of creating a new object on every invocation for constant
// data.
gbtCoinbaseAux = &btcjson.GetBlockTemplateResultAux{
Flags: hex.EncodeToString(btcscript.NewScriptBuilder().
AddData([]byte(coinbaseFlags)).Script()),
}
)
// Errors
@ -93,7 +110,7 @@ var rpcHandlersBeforeInit = map[string]commandHandler{
"getblockchaininfo": handleUnimplemented,
"getblockcount": handleGetBlockCount,
"getblockhash": handleGetBlockHash,
"getblocktemplate": handleUnimplemented,
"getblocktemplate": handleGetBlockTemplate,
"getconnectioncount": handleGetConnectionCount,
"getcurrentnet": handleGetCurrentNet,
"getdifficulty": handleGetDifficulty,
@ -202,21 +219,39 @@ func newWorkState() *workState {
}
}
// gbtWorkState houses state that is used in between multiple RPC invocations to
// getblocktemplate.
type gbtWorkState struct {
sync.Mutex
lastTxUpdate time.Time
lastGenerated time.Time
prevHash *btcwire.ShaHash
minTimestamp time.Time
template *BlockTemplate
}
// newGbtWorkState returns a new instance of a gbtWorkState with all internal
// fields initialized and ready to use.
func newGbtWorkState() *gbtWorkState {
return &gbtWorkState{}
}
// rpcServer holds the items the rpc server may need to access (config,
// shutdown, main server, etc.)
type rpcServer struct {
started int32
shutdown int32
server *server
authsha [fastsha256.Size]byte
ntfnMgr *wsNotificationManager
numClients int32
statusLines map[int]string
statusLock sync.RWMutex
wg sync.WaitGroup
listeners []net.Listener
workState *workState
quit chan int
started int32
shutdown int32
server *server
authsha [fastsha256.Size]byte
ntfnMgr *wsNotificationManager
numClients int32
statusLines map[int]string
statusLock sync.RWMutex
wg sync.WaitGroup
listeners []net.Listener
workState *workState
gbtWorkState *gbtWorkState
quit chan int
}
// Start is used by server.go to start the rpc listener.
@ -459,11 +494,12 @@ func newRPCServer(listenAddrs []string, s *server) (*rpcServer, error) {
login := cfg.RPCUser + ":" + cfg.RPCPass
auth := "Basic " + base64.StdEncoding.EncodeToString([]byte(login))
rpc := rpcServer{
authsha: fastsha256.Sum256([]byte(auth)),
server: s,
statusLines: make(map[int]string),
workState: newWorkState(),
quit: make(chan int),
authsha: fastsha256.Sum256([]byte(auth)),
server: s,
statusLines: make(map[int]string),
workState: newWorkState(),
gbtWorkState: newGbtWorkState(),
quit: make(chan int),
}
rpc.ntfnMgr = newWsNotificationManager(&rpc)
@ -1206,6 +1242,357 @@ func handleGetBlockHash(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}
return sha.String(), nil
}
// updateBlockTemplate creates or updates a block template for the work state.
// A new block template will be generated when the current best block has
// changed or the transactions in the memory pool have been updated and it has
// been some time has passed since the last template was generated. Otherwise,
// the timestamp for the existing block template is updated (and possibly the
// difficulty on testnet per the consesus rules). Finally, if the
// useCoinbaseValue flag is flase and the existing block template does not
// already contain a valid payment address, the block template will be updated
// with a randomly selected payment address from the list of configured
// addresses.
//
// This function MUST be called with the state locked.
func (state *gbtWorkState) updateBlockTemplate(s *rpcServer, useCoinbaseValue bool) error {
lastTxUpdate := s.server.txMemPool.LastUpdated()
if lastTxUpdate.IsZero() {
lastTxUpdate = time.Now()
}
// Generate a new block template when the current best block has
// changed or the transactions in the memory pool have been updated and
// it has been at least gbtRegenerateSecond since the last template was
// generated.
var msgBlock *btcwire.MsgBlock
var targetDifficulty string
latestHash, _ := s.server.blockManager.chainState.Best()
template := state.template
if template == nil || state.prevHash == nil ||
!state.prevHash.IsEqual(latestHash) ||
(state.lastTxUpdate != lastTxUpdate &&
time.Now().After(state.lastGenerated.Add(time.Second*
gbtRegenerateSeconds))) {
// Reset the previous best hash the block template was generated
// against so any errors below cause the next invocation to try
// again.
state.prevHash = nil
// Choose a payment address at random if the caller requests a
// full coinbase as opposed to only the pertinent details needed
// to create their own coinbase.
var payAddr btcutil.Address
if !useCoinbaseValue {
rand.Seed(time.Now().UnixNano())
payAddr = cfg.miningAddrs[rand.Intn(len(cfg.miningAddrs))]
}
// Create a new block template that has a coinbase which anyone
// can redeem. This is only acceptable because the returned
// block template doesn't include the coinbase, so the caller
// will ultimately create their own coinbase which pays to the
// appropriate address(es).
blkTemplate, err := NewBlockTemplate(s.server.txMemPool, payAddr)
if err != nil {
errStr := fmt.Sprintf("Failed to create new block "+
"template: %v", err)
rpcsLog.Errorf(errStr)
return btcjson.Error{
Code: btcjson.ErrInternal.Code,
Message: errStr,
}
}
template = blkTemplate
msgBlock = template.block
targetDifficulty = fmt.Sprintf("%064x",
btcchain.CompactToBig(msgBlock.Header.Bits))
// Find the minimum allowed timestamp for the block based on the
// median timestamp of the last several blocks per the chain
// consensus rules.
chainState := &s.server.blockManager.chainState
minTimestamp, err := minimumMedianTime(chainState)
if err != nil {
return btcjson.Error{
Code: btcjson.ErrInternal.Code,
Message: err.Error(),
}
}
// Update work state to ensure another block template isn't
// generated until needed.
state.template = template
state.lastGenerated = time.Now()
state.lastTxUpdate = lastTxUpdate
state.prevHash = latestHash
state.minTimestamp = minTimestamp
rpcsLog.Debugf("Generated block template (timestamp %v, "+
"target %s, merkle root %s)",
msgBlock.Header.Timestamp, targetDifficulty,
msgBlock.Header.MerkleRoot)
} else {
// At this point, there is a saved block template and another
// request for a template was made, but either the available
// transactions haven't change or it hasn't been long enough to
// trigger a new block template to be generated. So, update the
// existing block template.
// When the caller requires a full coinbase as opposed to only
// the pertinent details needed to create their own coinbase,
// add a payment address to the output of the coinbase of the
// template if it doesn't already have one. Since this requires
// mining addresses to be specified via the config, an error is
// returned if none have been specified.
if !useCoinbaseValue && !template.validPayAddress {
// Choose a payment address at random.
rand.Seed(time.Now().UnixNano())
payToAddr := cfg.miningAddrs[rand.Intn(len(cfg.miningAddrs))]
// Update the block coinbase output of the template to
// pay to the randomly selected payment address.
pkScript, err := btcscript.PayToAddrScript(payToAddr)
if err != nil {
return btcjson.Error{
Code: btcjson.ErrInternal.Code,
Message: err.Error(),
}
}
template.block.Transactions[0].TxOut[0].PkScript = pkScript
template.validPayAddress = true
// Update the merkle root.
block := btcutil.NewBlock(template.block)
merkles := btcchain.BuildMerkleTreeStore(block.Transactions())
template.block.Header.MerkleRoot = *merkles[len(merkles)-1]
}
// Set locals for convenience.
msgBlock = template.block
targetDifficulty = fmt.Sprintf("%064x",
btcchain.CompactToBig(msgBlock.Header.Bits))
// Update the time of the block template to the current time
// while accounting for the median time of the past several
// blocks per the chain consensus rules.
UpdateBlockTime(msgBlock, s.server.blockManager)
msgBlock.Header.Nonce = 0
rpcsLog.Debugf("Updated block template (timestamp %v, "+
"target %s)", msgBlock.Header.Timestamp,
targetDifficulty)
}
return nil
}
// blockTemplateResult returns the current block template associated with the
// state as a btcjson.GetBlockTemplateResult that is ready to be encoded to JSON
// and returned to the caller.
//
// This function MUST be called with the state locked.
func (state *gbtWorkState) blockTemplateResult(useCoinbaseValue bool) (*btcjson.GetBlockTemplateResult, error) {
// Convert each transaction in the block template to a template result
// transaction. The result does not include the coinbase, so notice
// the adjustments to the various lengths and indices.
template := state.template
msgBlock := template.block
numTx := len(msgBlock.Transactions)
transactions := make([]btcjson.GetBlockTemplateResultTx, 0, numTx-1)
txIndex := make(map[btcwire.ShaHash]int64, numTx)
for i, tx := range msgBlock.Transactions {
txHash, _ := tx.TxSha()
txIndex[txHash] = int64(i)
// Skip the coinbase transaction.
if i == 0 {
continue
}
// Create an array of 1-based indices to transactions that come
// before this one in the transactions list which this one
// depends on. This is necessary since the created block must
// ensure proper ordering of the dependencies. A map is used
// before creating the final array to prevent duplicate entries
// when mutiple inputs reference the same transaction.
dependsMap := make(map[int64]struct{})
for _, txIn := range tx.TxIn {
if idx, ok := txIndex[txIn.PreviousOutpoint.Hash]; ok {
dependsMap[idx] = struct{}{}
}
}
depends := make([]int64, 0, len(dependsMap))
for idx := range dependsMap {
depends = append(depends, idx)
}
// Serialize the transaction for later conversion to hex.
txBuf := bytes.NewBuffer(make([]byte, 0, tx.SerializeSize()))
if err := tx.Serialize(txBuf); err != nil {
return nil, btcjson.Error{
Code: btcjson.ErrInternal.Code,
Message: err.Error(),
}
}
resultTx := btcjson.GetBlockTemplateResultTx{
Data: hex.EncodeToString(txBuf.Bytes()),
Hash: txHash.String(),
Depends: depends,
Fee: template.fees[i],
SigOps: template.sigOpCounts[i],
}
transactions = append(transactions, resultTx)
}
// Generate the block template reply.
header := &msgBlock.Header
reply := btcjson.GetBlockTemplateResult{
Bits: strconv.FormatInt(int64(header.Bits), 16),
CurTime: time.Now().Unix(),
Height: template.height,
PreviousHash: header.PrevBlock.String(),
SigOpLimit: btcchain.MaxSigOpsPerBlock,
SizeLimit: btcwire.MaxBlockPayload,
Transactions: transactions,
Version: header.Version,
}
if useCoinbaseValue {
reply.CoinbaseAux = gbtCoinbaseAux
reply.CoinbaseValue = &msgBlock.Transactions[0].TxOut[0].Value
} else {
// Ensure the template has a valid payment address associated
// with it when a full coinbase is requested.
if !template.validPayAddress {
return nil, btcjson.Error{
Code: btcjson.ErrInternal.Code,
Message: "A coinbase transaction has been " +
"requested, but the server has not " +
"been configured with a payment " +
"addresses via --miningaddr",
}
}
// Serialize the transaction for conversion to hex.
tx := msgBlock.Transactions[0]
txHash, _ := tx.TxSha()
txBuf := bytes.NewBuffer(make([]byte, 0, tx.SerializeSize()))
if err := tx.Serialize(txBuf); err != nil {
return nil, btcjson.Error{
Code: btcjson.ErrInternal.Code,
Message: err.Error(),
}
}
resultTx := btcjson.GetBlockTemplateResultTx{
Data: hex.EncodeToString(txBuf.Bytes()),
Hash: txHash.String(),
Depends: []int64{},
Fee: template.fees[0],
SigOps: template.sigOpCounts[0],
}
reply.CoinbaseTxn = &resultTx
}
return &reply, nil
}
// handleGetBlockTemplateRequest is a helper for handleGetBlockTemplate which
// deals with generating and returning block templates to the caller. It
// detects the capabilities reported by the caller in regards to whether or not
// it supports creating its own coinbase (the coinbasetxn and coinbasevalue
// capabilities) and modifies the returned block template accordingly.
func handleGetBlockTemplateRequest(s *rpcServer, request *btcjson.TemplateRequest) (interface{}, error) {
// Extract the relevant passed capabilities and restrict the result to
// either a coinbase value or a coinbase transaction object depending on
// the request. Default to only providing a coinbase value.
useCoinbaseValue := true
if request != nil {
var hasCoinbaseValue, hasCoinbaseTxn bool
for _, capability := range request.Capabilities {
switch capability {
case "coinbasetxn":
hasCoinbaseTxn = true
case "coinbasevalue":
hasCoinbaseValue = true
}
}
if hasCoinbaseTxn && !hasCoinbaseValue {
useCoinbaseValue = false
}
}
// When a coinbase transaction has been requested, respond with an error
// if there are no addresses to pay the created block template to.
if !useCoinbaseValue && len(cfg.miningAddrs) == 0 {
return nil, btcjson.Error{
Code: btcjson.ErrInternal.Code,
Message: "A coinbase transaction has been requested, " +
"but the server has not been configured with " +
"a payment addresses via --miningaddr",
}
}
// Return an error if there are no peers connected since there is no
// way to relay a found block or receive transactions to work on.
// However, allow this state when running in the regression test or
// simulation test mode.
if !(cfg.RegressionTest || cfg.SimNet) && s.server.ConnectedCount() == 0 {
return nil, btcjson.ErrClientNotConnected
}
// No point in generating or accepting work before the chain is synced.
_, currentHeight := s.server.blockManager.chainState.Best()
if currentHeight != 0 && !s.server.blockManager.IsCurrent() {
return nil, btcjson.ErrClientInInitialDownload
}
// Protect concurrent access when updating block templates.
state := s.gbtWorkState
state.Lock()
defer state.Unlock()
// Get and return a block template. A new block template will be
// generated when the current best block has changed or the transactions
// in the memory pool have been updated and it has been at least five
// seconds since the last template was generated. Otherwise, the
// timestamp for the existing block template is updated (and possibly
// the difficulty on testnet per the consesus rules).
if err := state.updateBlockTemplate(s, useCoinbaseValue); err != nil {
return nil, err
}
return state.blockTemplateResult(useCoinbaseValue)
}
// handleGetBlockTemplate implements the getblocktemplate command.
//
// See https://en.bitcoin.it/wiki/BIP_0022 for more details.
func handleGetBlockTemplate(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
c := cmd.(*btcjson.GetBlockTemplateCmd)
request := c.Request
// Set the default mode and override it if supplied.
mode := "template"
if request != nil && request.Mode != "" {
mode = request.Mode
}
// The only supported mode is currently "template". Use a switch to
// make other modes easier to implement.
switch mode {
case "template":
return handleGetBlockTemplateRequest(s, request)
}
return nil, btcjson.Error{
Code: btcjson.ErrInvalidParameter.Code,
Message: "Invalid mode",
}
}
// handleGetConnectionCount implements the getconnectioncount command.
func handleGetConnectionCount(s *rpcServer, cmd btcjson.Cmd, closeChan <-chan struct{}) (interface{}, error) {
return s.server.ConnectedCount(), nil